Fuze safety device



Jan. 19, 19 0 Filed Aug. 25, 1950 'FIG.

C. R. HAMILTON FUZE SAFETY DEVICE 3 Sheets-Sheet l INVENTOR.

CHARLES R. HAMILTON ATTORNEY Jan. 19, 1960 c. R. HAMILTON 2,92

FUZE SAFETY DEVICE Filed Aug. 25, 1950 3 Sheets-Sheet 2 6 4 INVENTOR.

CHARLES R. HAMILTON BY 4? 6%...

ATTORNEY Jan. 19, 1960 c. R. HAMILTON FUZE SAFETY DEVICE Filed Aug. 25, 1950 3 Sheets-Sheet 3 F I G.

44 4:2 1 4 12 I I x40 H FIG. 5 E

la 2! 'f t: 3 27 28 i MT-51;}

INVENTOR.

CHARLES R. HAMILTON ATTORNEY FUZE SAFETY DEVICE Charles R. Hamilton, Socorro, N. Mex., assignor to the United States of America as represented by the Secretary of the Navy Application August 25, 1950, Serial No. 181,479

4 Claims. (Cl. 102-79) The present invention relates to an improved contact fuze for an explosive projectile.

More particularly the invention relates to a novel safety device and arming mechanism for a contact fuze.

Much trouble has been experienced with accidental explosions in the storage and handling of projectiles which utilize contact fuzes. Because it was impossible always to control the manner in which the fuzes would be handled, the need arose for a safety device that would prevent accidental explosions of the main charge of a projectile, but which nevertheless would assure proper'operation upon coming in contact with a target. The fuze safety device which constitutes the present invention was developed to meet this need.

Broadly, this device consists of a gate which interrupts the powder train between the detonator and the booster charge, and which prevents the booster, and therefore the main charge of the projectile, from exploding should the firing pin mechanism 'be tripped prematurely. Upon the projectile being fired from a gun, the gate moves out from between-the detonator and the booster charge and reestablishes the powder train to the main charge. In order to maintain the gate in the latter position, and thereby assure proper operation of the exploding mechanism upon impact with a target, the fuze safety device further incorporates a novel locking mechanism which serves to maintain the safety device in the armed position even under severe laterally applied forces, such as would occur should the shell strike an object with a glancing blow before hitting. thetarse It is therefore one object of the present invention to provide a contact fuze for explosive projectiles which will prevent accidental explosions of said projectiles while being handled.

Another object of the invention is to provide a safety contact fuze for an explosive projectile which will move to armed position, upon the firing of the projectile.

Other objects and many of the attendant advantages of this invention will be appreciated readilyvas the same becomes understood by reference to the following detailed description, when considered in connection with the accompanying drawings, wherein: v

Fig. l is a fragmentary view,.partly in axial section, of a projectile having a contact fuze, which includes the improved safety device; I

2 is a cross-section, in the plane 22 of Fig. 1, showing the improved safety device in the armed position;

Fig. 3 is a cross-section similar to Fig. 2 but show ing the improved safety device in the unarmed position;

Fig. 4 is a longitudinal section taken in the two planes indicated by line 4-4 of Fig. 2, showing the improved safety device in the armed position; and 1 Fig. 5. is a longitudinal sectional view taken in the two planes indicated by line 5-5 of Fig. 2 and showing the auxiliary locking means.

2,921,526 Patented Jan. 19, IBM) Referring now to Fig. 1 of the drawings, there is shown for completeness the forward end of a projectile 2, slightly broken away, which has a threaded cylindrical after portion 3. Projectile 2 has therein a forward chamber 4, a central chamber 5, and a rear chamher 6, said chambers having their longitudinal axes coinfiled by L. P. Granath and S. S. Podnos, July 6, 1948,

for a Selective Delayed Action Fuze, and form no part of the present invention, and hence are not discussed further herein.

Situated in central chamber 5 is a fuze safety device that'embodies the present invention. This device is described more fully hereinafter; at present, for the purpose of illustrating its function, it may be explained merely that in the armed position, the device serves to establish a continuous powder train between a detonating charge exposed to the action of firing pin 8, and a booster charge 9 contained within the rear chamber 6.

For a detailed description of the fuze safety device, reference is now made to Figs. 2 through 5 of the draw ings. Referring first to Fig. 4, the safety device com- 1 prises a housing A which includes a pair of cylindrical blocks 10 and 12 that are separated by a partition 14, said blocks and partition being suitably secured together, as a plurality of rivets 15, and 1501, as seen in Figs; 2 and, 3. An axially located orifice 16 is provided in the partition 14, for a purpose that is explained below. The forward block 10 has a centrally disposed cylindrical chamber 17, and mounted in this chamber is a detonator 18-containing a percussion explosive, such as tetryl lead.

The chamber 17 is axially alined with a second chamber 21 formed in the rearward portion of block 12, and which carries the percussion explosive 9 constituting a portion of the booster charge of the projectile. When the parts are in the armed position, chamber 17 communicates through the centralorifice 16 in partition 14 r with a third chamber 23 that, as is best shown in Fig. 2,

' cylindrical chamber 27 formed in the forward face of block 12, and is pivoted about a shaft 28. Chamber 23 contains a percussion explosive pellet 24, which may be rotated in and out of axial alinement with chambers 17 and 23.

'Thus, as is best shown in Fig. 3, when in unarmed position, rotor 26 acts as a movable barrier or gate preventing an accidental explosion of the detonator 18 from traveling to the main explosive charge of the projectile. Upon firingtlze projectile in which the device is mounted, the heavy end of the gate or rotor 26 is swung outward bycentrifugal force, due to projectile spin, tothe armed position shown in Fig. 2. One of the rivets, 15a, may be placed as shown in Figs. 2 and 3, to act also as a stopfor positioning the gate or rotor 26 in armed position, when engaged by a corner of said rotor, as shown in Fig. 2. .In this position, explosive pellet 24 is alined with detonator 18 and charge 9, thus establishing a powder train from saidpellet 18, which is designed and positioned to be acted upon by the firing pin 8 to the main explosive charge of the projectile;

In order to assure proper operation of the contact fuze upon impact witha target, the safety device incorporates A anovel locking mechanism which prevents the gate or rotor 26 from pivoting chamber 23 out of alinementafter the projectile has been fired. With reference toEig. 2, thislmechanism comprises a bore 29 formed in rotor 26, and extending inwardly from the curved surface of the rotor toward chamber-i23. Bore'29 has a furtheraxial extension bore 30 of asmaller diameter extending'im,

wardly toward chamber 23 and forming a shoulder 32; As is best seen in Fig. 3, in the unarmed position, shoulder 32 supports a detent 34 having a slender stem 36 that projects into bore 30. When the rotor 26 is turned to the armed position, as illustrated in Fig. 2, detent 34 slips into an orifice 38 that then is alined with bore 29, and that extends from the cavity 27 through block 12 to its outer surface. a

" To supplement the locking action of detent 34, the I jectile in which the'armin'g mechanism is'mounted strike anobject with a lateral or glancing blow, slug 41 slides forward into bore 39, thereby locking rotor 26 in the armed position. This locking arrangement is independent of and supplementary to the locking action of detent 34. a Y

Referring again to Fig. 3, gateor rotor 26 is retained in the unarmed position by a primary, cross-shaped detent 42 having a pair of tapered wings 49. The inner end of primary detent 42 fits into arectangular notch 43 cut in the periphery ofrotor 26, and said detent is slidably supported in a first, radially extending groove 44 formed in the forward face of block 12, with the wings of the detent extending into a second, chordally disposed, transverse groove 46. Transverse groove 46 is also formed in the forward face of block 12, and intersects groove 44 at right angles. V The inclined surfaces of the tapered wings 49 of detent 42 bear against the supplementary inclined surfaces 48 of a pair of secondary detents 50 which are slidably mounted in the transverse groove 46, and urged toward primary detent 42 .in a wedging action, which is produced by a pair'of coiled springs 52 acting against a pair of fixed blocks 54 mounted inthe respective ends of the groove 46, and which is sufiiciently strong to maintain detent 42 depressed into rectangular notch 43 even under severe shocks, such as would occur if the assembly-were accidentally dropped from a considerable height while being handled. V p

While the operation of the invention will presumably be clear from the structure disclosed, it may be well to summarize it briefly as follows: With reference to Fig. 3, when the projectile in which the fuze is mounted is it extremely improbable that a large lateral force will cause disengagement of the detent from the orifice 38.

Referring now to Fig. 5, should the projectile be subjected to a laterally applied force by the projectile striking Obviously. many modifications and variations of the present invention are possible in the light of .the'above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is: V V l. A safety device fora projectile fuze, including a cylindrical housing having therein an oif-center chamber fired, and acquires spin, the secondary detents 50 move out by centrifugal force, against springs'52, releasingthe primary detent 42, which then moves radially outward and unlocks rotor 26. Rotor 26 then turns, due to centrifugal force, as already explained, toward the armed position shown in Fig. 2, and alines chamber 23 with detonator 18, radial bore 29 with orifice 38, and bore '39 with bore 40. When bore 29 is properly alinedwith orifice 38, the detent 34 moves outward and enters said orifice 38 to lock rotor 26 in the armed position. As soon as the detent 34 has thus moved outward to its locked position, stem 36 of the-detent falls clear of the axial bore extension 30 and misalines the axis or detent 34 and that ofthe bore 30. Any inward motion of the detent occurring thereafter will merely bring the end of V the stem 36 into contact with shoulder 32, thereby making and having a passage extending substantially radially from said chamber through said housing, a detonator and an explosive charge secured axially in opposite ends of said housing, ajgate' pivotally mounted within the chamber and initially interposed between thedetonator and the explosive charge, said gate having a chordallydirected bore therein that may be brought substantially into register with'the said passage, said bore having at its. inner end an, extension of'reduced diameter with a shoulder between the bore and the extension, a detent housed in said bore, and having a stem at its inner end fittinginto said extension, said -detent'being 'movable partly out of the bore when said bore is in register withits center of gravity lies closer to the axis of the pro.- jectile than the pivot of said gate so that centrifugal force will cause the gate to rotate about its pivot, when projectile spin exists, to cause the detent to become engaged in the passage.

3. A safety device. for a projectile fuze, includinga housinghaving an elf-center chamber formed therein, a detonator and an explosive charge, secured axially in the housing at opposite ends of the chamber, a pivotally mounted .gate in the chamber and initially interposed between said detonator and said charge, an explosive pellet 'mounted in said gate, the gate being rotatable from its initial position to a second position by centrifugalforce to interpose said pellet between the detonator and said charge, said gate having a chordally directed bore therein witha shorter, smaller-diameter bore at 'its inward end, forming a shoulder at the junction of and fitting slidably in the larger bore and having a stem extending from the inward end of said body portion and projecting into. the smaller bore, the housinghaving an aperture therein placed to register with the larger bore when-the pellet is alined between the detonator and the explosive charge, whereby due to centrifugal force the outer end-of said'detent'will enter said aperture .when such alinement exists whereby the stem will be withdrawn from the smaller bore and will lodge againstthe shoulder, preventing the full return of the detentinto the bore and thus locking the gate against rotation.

4.'A safety device for a projectile fuzeyincluding a housing having an ofl-center. chamber formed therein, a detonator and anexplosive charge securedaxially in the housing at opposite ends of the chamber, a gate between said detonator and said charge, an explosive pellet mounted in said gate, the gate being rotatable from its initial position to a second position to interpose said pellet between the detonator and the explosive charge, said housing having an orifice extending substantially radially from said chamber, said gate having a chordally directed bore that is in substantial registry with said orifice when said gate is in said second position, said bore having at its inner end an extension of reduced diameter with a shoulder between said bore and said extension, a detent housed in said bore and having a stem at its inner end fitting into said extension, said detent being movable by centrifugal influences partly out of the bore and partly into said orifice when said gate is in its second position for locking said gate to the housing, said stem being engageable with said shoulder to prevent a subsequent retraction of said detent, a pri- References Cited in the file of this patent UNITED STATES PATENTS 1,550,977 Lukens Aug. 25, 1925 1,561,687 Brayton Nov. 17, 1925 1,715,513 Rogers June 4, 1929 1,755,279 Teitscheid Apr. 22, 1930 1,792,631 Deevy Feb. 17, 1931 2,068,708 Reed Jan. 26, 1937 2,118,062 Woodberry May 24, 1938 

